Pharmaceutical preparations such as cut or ground drugs and foods, e.g. cut or ground spice drugs, may not be degerminated in Germany and some other countries by means of highly effective methods corresponding to the state of the art. These especially include the treatment of the drug material with germ-reducing methods using ionising radiation, e.g. cobalt 60 or linear acceleration, and the chemical process of exposure to ethylene oxide gas. Even though such radiation processes for reducing germs in plant drugs or foods are among the most effective methods, national laws prohibiting their use have been passed as a result of severe concern in connection with the risk of the development of toxic substances.
Even so-called mild processes such as the hydrothermal process and the treatment with live steam may cause detrimental changes in the material to be degerminated. This is especially true for drug materals containing sensitive essential oils which may be changed with regard to both pharmacology and taste by such processes. Such a hydrothermal method also causes a loss of ingredients. For understandable reasons, all those disadvantages are undesirable. The above-mentioned disadvantages should also be avoided for ecological reasons, because the loss in active ingredient leads to increased consumption of plant material.
A particularly severe disadvantage of the hydrothermal processes lies in the fact that they are conducted a high temperatures, e.g. a saturated steam temperature between 110 and 160.degree. C. This shows that even though drugs containing essential oils may be degerminated, they will unfortunately lose their original characteristics. In addition to a physical reduction of substances in the starting material, chemical changes occur which result in irreversible conversion or decomposition of additional ingredients of the drug material. Both the high temperatures of such hydrothermal degermination processes and radiation generate oxygen radicals which cause irreversible changes to the flavonoid and polyphenol content of the drug material. In case of exposure to ethylene oxide gas, carcinogenic interim products of the plant ingredients develop, which should be avoided in any case.
These known processes have also shown that extensive reduction of, for example, mould fungi is very difficult, because the micro-organisms form persistent spores. Due to their characteristics, such germs and their spores, respectively, tend to amplify when left standing after sterilisation at sometimes severe conditions.
The limits for the germ content of, for example, plant drugs have been defined in DAB 10 (German pharmacopoeia, Volume 10) for medicaments containing such materials. Therefore, drugs must be discarded, because they do not correspond to the strict requirements of pharmacopoeias, e.g. DAB 10, even though they would have been suitable for use under chemical or pharmaceutical aspects.
DAB 10 defines the following maximum germ content for plant drug preparations: 10.sup.5 for aerobes, 10.sup.3 for fungi and yeasts, 10.sup.3 for enteric bacteria, 10.sup.1 for E. coli. Salmonella must not be contained. Concerning plant drugs such as drug teas, the germ content of which is reduced by scalding before use, or plant drug preparations for external application, the maximum germ content according to DAB is higher, namely 10.sup.7 for aerobes, 10.sup.4 for fungi and yeasts, 10.sup.4 for enteric bacteria, 10.sup.2 for E. coli and 0 for salmonella per gram of material. Similar values are prescribed in the European Pharmacopoeia which became nationally effective on Jan. 1, 1996, and permits as much as 10.sup.4 for fungi intended for internal application. However, no E. coli or salmonella germs must be present. The recommendation issued by the German expert committee for drug, spice and flavouring plants of the producers of drug and spice plants for the maximum germ content are analogous to DAB 10, so that the same maximum germ contents must be observed. The Swiss pharmacopoeia (Pharmacopoeia Helvetica VII) permits a maximum germ content of 10.sup.4 /g for yeasts, no visible moulding being permitted with regard to mould fungi. The maximum permitted content for E. coli is 10.sup.2 /g. Salmonella should not be detectable at all.
Experience has shown that observation of the pharmacopoeia regulations or recommendations of the expert committees is very difficult without, as outlined above, reducing the active ingredient content of the drug or changing its chemical structure and pharmacological activity in an undesirable manner.